U.S. Pat. No. 3,503,294 of Joseph Vinciguerra and James A. Henigan discloses a sawing machine having several blades with serrated edges capable of producing closed figures cut from a flat surface as, for example, squares, rectangles, polygons such as pentagons, hexagons, and the like, and circles or ellipses. In this device, the drive plates may be star shaped.
Unfortunately, U.S. Pat. No. 3,503,294 has the following drawbacks:
1.transfer of rotary torque power from a rotating shaft assembly to a reciprocating driving plate is not uniform and often gives rise to severe vibrations when operated much in excess of 1200 revolutions per minute; PA1 2.the driving plate may directly contact a wall's surface while such wall is being cut by reciprocating saw blades and become damaged; PA1 3.there is a tendency, in some instances, for the driving plate or the saw retaining plates to twist and bind when certain torque levels are exceeded; thereby limiting the degree of useful torque that can be utilized; PA1 4.any angled contact of the cutting edges with the surface which is to be cut usually results in a buckling of the drive plate and a binding of the cutting blades.